Facebook users are being encouraged to double-check their privacy settings after the social network introduced an update to its search feature which adds almost 2 trillion older posts by its members to the index.

Previously, Facebook’s search feature was largely limited to groups, events and locations, with individuals’ public posts difficult to find without directly navigating to the user’s profile page.

Now, the site has indexed more than 2trn posts, and the search function enables users to seek out a specific post from any public profile, whether or not the two are friends on the site.

In a post, Tom Stocky, the site’s VP of search, said : “When you search, you’ll now see the most recent, relevant public posts along with posts from your friends. Search results are organised to help you cut through the noise and quickly understand what the world is saying about a topic in the moment. You also can pull-to-refresh and see the latest public posts.”

But the new feature has led to concern that posts which many would rather stay hidden will be revealed to the world. Stocky says: “Your search results are personalised and unique to you and, as always, you can only see things that have been shared with you. Likewise, you control who can see your posts on Facebook and it’s easy to change the audience of your past posts any time.”

With some users having over a decade of past posts indexed on the site, however, it is possible that users may not remember which posts were made with which privacy settings, which could lead to some uncomfortable posts resurfacing.

The change is part of a push on the part of Facebook to compete with main rival Twitter on live events, something where the latter’s broad search and chronological focus has given it the edge.

Recent introductions such as Facebook’s “trending” bar have let users search the site for current events, but until this most recent change, it was difficult to find and take part in the public conversation around what was going on in the wider world.